Effect of salt stress on some physiological parameters in Atriplex halimus L.

The impact of salinity applied for five weeks followed two provenances of Atriplex halimus L. harvested from Oran (Algeria coast) and Ain Dheb (high plateaus west of Algeria). The analyzed parameters are physiological from the leaves of young plants grown in a greenhouse stored in air-conditioned glass. Two types of salt stress are imposed on plants from the 165th day after sowing for a batch CaCl2 + NaCl to 300 meq and 600 meq.l-1and for the other batch to undiluted water sea with a frequency of watering every other two days. The results of water indicators such as the relative water content (RWC or TRE) showed some fluctuation during the five weeks under the two types of stress. Transpiration (water loss from the excised leaf or RWL) measured after 30, 60 and 120 min at the end of the period of application of stress presents a decline in both sources and types of stress. In addition, the stomatal resistance showed considerable variability for both sources and the type of stress.Keywords: A. halimus L., salt stress NaCl + CaCl2, Seawater, RWC, sweating, stomatal resistance

A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

Solution of the Percus-Yevick equation for hard discs

We solve the Percus-Yevick equation in two dimensions by reducing it to a set of simple integral equations. We numerically obtain both the pair correlation function and the equation of state for a hard disc fluid and find good agreement with available Monte-Carlo calculations. The present method of resolution may be generalized to any even dimension.Comment: 9 pages, 3 figure

The spectrum of large powers of the Laplacian in bounded domains

We present exact results for the spectrum of the Nth power of the Laplacian in a bounded domain. We begin with the one dimensional case and show that the whole spectrum can be obtained in the limit of large N. We also show that it is a useful numerical approach valid for any N. Finally, we discuss implications of this work and present its possible extensions for non integer N and for 3D Laplacian problems.Comment: 13 pages, 2 figure

Capillary deformations of bendable films

We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding establishes a new type of “soft capillarity” that stems from the bendability of thin elastic bodies rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle noticed in several previous attempts to model “drop-on-a-floating-sheet” experiments, and enabling a reliable usage of this setup for the metrology of ultrathin films

Casimir Effects in Renormalizable Quantum Field Theories

We review the framework we and our collaborators have developed for the study of one-loop quantum corrections to extended field configurations in renormalizable quantum field theories. We work in the continuum, transforming the standard Casimir sum over modes into a sum over bound states and an integral over scattering states weighted by the density of states. We express the density of states in terms of phase shifts, allowing us to extract divergences by identifying Born approximations to the phase shifts with low order Feynman diagrams. Once isolated in Feynman diagrams, the divergences are canceled against standard counterterms. Thus regulated, the Casimir sum is highly convergent and amenable to numerical computation. Our methods have numerous applications to the theory of solitons, membranes, and quantum field theories in strong external fields or subject to boundary conditions.Comment: 27 pp., 11 EPS figures, LaTeX using ijmpa1.sty; email correspondence to R.L. Jaffe ; based on talks presented by the authors at the 5th workshop `QFTEX', Leipzig, September 200

Phase-Field Approach for Faceted Solidification

We extend the phase-field approach to model the solidification of faceted materials. Our approach consists of using an approximate gamma-plot with rounded cusps that can approach arbitrarily closely the true gamma-plot with sharp cusps that correspond to faceted orientations. The phase-field equations are solved in the thin-interface limit with local equilibrium at the solid-liquid interface [A. Karma and W.-J. Rappel, Phys. Rev. E53, R3017 (1996)]. The convergence of our approach is first demonstrated for equilibrium shapes. The growth of faceted needle crystals in an undercooled melt is then studied as a function of undercooling and the cusp amplitude delta for a gamma-plot of the form 1+delta(|sin(theta)|+|cos(theta)|). The phase-field results are consistent with the scaling law "Lambda inversely proportional to the square root of V" observed experimentally, where Lambda is the facet length and V is the growth rate. In addition, the variation of V and Lambda with delta is found to be reasonably well predicted by an approximate sharp-interface analytical theory that includes capillary effects and assumes circular and parabolic forms for the front and trailing rough parts of the needle crystal, respectively.Comment: 1O pages, 2 tables, 17 figure

Evolution du Facteur de résistance hygrothermique transitoire en fonction des séquences d'empilement pour des composites stratifiés sous des conditions d'environnement cycliques

Exposé à des conditions d'environnement cycliques, les composites à matrices polymères sont capables d'absorber une quantité d'humidité durant de longues années de service. Suite à ce type d'environnement, il se développe des contraintes hygrothermiques extrêmement critiques aux bords et aux interfaces fibres/résines. Au cours des premiers temps de la diffusion d'humidité, les contraintes hygrothermiques sont assez importantes dans la direction transversale, où elles peuvent engendrées un délaminage par gonflement entre les plis formants le stratifié. Pour avoir une idée sur la probabilité d'endommagement des plaques stratifiées sous des contraintes hygrothermiques transitoires, on a adopté le critère de rupture de Tsai-Wu. Le critère de sécurité sera vérifier en évaluant le facteur de résistance (R) pour chaque séquence d'empilement aux bords de la plaque stratifiée

Dynamique phytoécologique du Thuya de Berbérie face à l'incendie

Le thuya de Berbérie est une espèce endémique de l'Afrique du Nord. Longtemps considérée comme une essence forestière sans grand intérêt, les écologues et les forestiers insistent aujourd'hui sur la place éminente qu'elle joue dans la structuration des paysages végétaux du Maghreb, mais aussi sur sa valeur forestière et économique. Sa régression actuelle en Algérie est donc très inquiétante. Cet article se propose de mieux connaître cette essence en étudiant son comportement à travers différents paramètres dendrométriques